 However, since the release of "Kind of Blue" by Miles Davis, jazz improvisation has come to include modal harmony and improvisation over static key centers, while the emergence of free jazz has led to a variety of types of improvisation, such as "free blowing", in which soloists improvise freely and ignore the chord changes.Jazz improvisation can be divided into soloing and accompaniment.When soloing, a performer (instrumentalist or singer) creates a new melodic line to fit a song's chord progression.